Currently, environmental disasters caused by global warming and the resulting weather changes are becoming more severe every day. One of the major causes of global warming is the emission of carbon dioxide by the use of fossil fuels and the resulting air pollution. One of the major causes of carbon dioxide emissions is exhaust gas from vehicles. For this reason, in advanced countries including Europe and the USA, vehicle fuel economy regulations have been provided, and fuel economy regulations are also being more stringent every day. The best way to increase vehicle fuel economy is to reduce the weight of vehicles. For this purpose, in the steel field, many studies have been conducted to improve high strength and high ductility properties. In addition, in recent years, the need for high strength and high ductility lightweight steel sheets having low density together with high strength and high ductility properties has increased.
Prior art documents related to the present invention include Korean Laid-Open Patent Publication No. 10-2006-0071618 (published on Jun. 27, 2006), entitled “High-manganese steel having excellent abrasion resistance and impact resistance and method for producing the same”.